Tin zinc oxide (SnZnO3)

Endpoint summary

Additional information

4.1 Appearance/physical state/colour

The test material was determined upon visual inspection to be a fine, white powder.

As part of a study to determine the physico-chemical properties of the test material, conducted to standardised guidelines and GLP, the appearance and physical state of the test material was assessed by visual inspection and was determined to be a fine white powder.

 

4.2 Melting point/freezing point

In the key study, it was attempted to determine the melting point of the test material using the capillary method in accordance with GLP and the standardised guidelines OECD 102 and EU Method A.1. The test material did not show any sign of melting below 360 °C, which was the upper temperature limit for the apparatus used. Thus the melting point, although not determinable by this method, is >360 °C.

 

Supporting information is provided in the form of a second study in which the melting temperature of the test material was assessed in accordance with GLP using a method designed to comply with the standardised guideline EU Method A.1. The determination was carried out using the capillary method and metal block apparatus. No sign of melting or decomposition was noted up to a temperature of 630 K.

 

4.3 Boiling point

In accordance with Section 7.3, Column 2 of REACH Annex VII, it is considered appropriate to omit the boiling point study as the substance has been determined to have a melting point >360 °C.

 

4.4 Density

The relative density of the test material was determined in the key study in accordance with GLP and the standardised guidelines OECD 109 and EU Method A.3.

The density of the test material was determined relative to bi-distilled water using a pycnometer at 20 °C (293.15 K) and bi-distilled water was also employed as the displacing vehicle.

The relative density was found to be 5.408.

 

Supporting information is available in the form of a second study in which the relative density of the test material was investigated in accordance with GLP using a method designed to comply with the standardised guideline EU Method A.3.

The density was determined relative to water using a pycnometer with an immersion liquid. The test was carried out at 20.5 °C using hexane as the immersion liquid.

The relative density of the test material was determined to be 3.8777 at 20.5 °C.

 

4.6 Vapour pressure

In accordance with Section 7.5, Column 2 of REACH Annex VII, it is considered appropriate to omit the vapour pressure study as the substance has been determined to have a melting point >360 °C.

 

4.7 Partition coefficient

In accordance with Section 7.8, Column 2 of REACH Annex VII, it is considered appropriate to omit the partition co-efficient study as the substance is inorganic.

 

4.8 Water solubility

A study was carried out to determine the water solubility of the test material in accordance with GLP and the standardised guideline EU Method A.6.

The investigation was carried out using the column elution method with a recirculating pump and the water solubility was determined to be 13 mg/L at 20.0 ± 0.5 °C.

 

4.9 Solubility in organic solvents / fat solubility

In the key study, the solubility of the test material in fat was determined in accordance with GLP and the standardised guidelines OECD 116 and EC Method A.7.

The solubility of the test material in HB 307 standard fat simulant was determined to be 0.32 mg/100 g of fat at 37 °C.

 

Supporting information is provided in the form of a second study that investigated the solubility of the test material in fat that was carried out in accordance with GLP and the standardised guideline EU Method A.7.

The solubility of the test material in HB 307 standard fat simulant was determined to be 0.823 mg/100 g of fat at 37 °C.

 

4.10 Surface tension

The surface tension of a 90 % saturated solution of the test material was determined in accordance with GLP and the standardised guideline EU Method A.5.

The concentration of test material in the solution was determined to be 2.9 mg/L. The surface tension was determined on a Surface Tensiometer (ISO ring method) and was found to be 71.4 mN/m at 21.2 ± 0.3 °C.

 

4.11 Flash point

In accordance with Section 7.9, Column 2 of REACH Annex VII, it is considered appropriate to omit the flash point study as the substance is an inorganic solid.

 

4.12 Auto flammability

The auto-flammability of the test material was investigated in accordance with GLP and the standardised guideline EU Method A.16.

The test material was heated to the upper temperature limit for the test, 400 °C, without self-ignition. Therefore the test material is not auto-flammable.

 

4.13 Flammability

The flammability of the test material was investigated in accordance with GLP and the standardised guideline EU Method A.10.

The test material was formed into a pile 250 mm long and several attempts were made to ignite one end of the pile using a butane/air flame.

The test material did not ignite. It is non-flammable with respect to this test.

In accordance with the criteria for classification as defined in Annex I, Regulation 1272/2008, the test material does not require classification as it does not meet the conditions specified for Flammable Solids.

 

4.14 Explosiveness

In accordance with Section 7.11, Column 2 of REACH Annex VII, it is considered appropriate to omit the determination of explosive properties study as there are no chemical groups associated with explosive properties present in the molecule.

 

4.15 Oxidising properties

In accordance with Section2 of REACH Annex XI, it has been considered appropriate to omit this test on the basis that it is not technically feasible. Studies conducted to address other endpoints, namely melting point and flammability, show that the test material does not ignite and decomposes at temperatures above 360 °C. Furthermore, the column 2 adaptation of REACH Annex VII, section 7.13, states that the test need not be conducted if the substance is incapable of reacting exothermically with combustible materials, for example on the basis of the chemical structure. As the material contains two metal ions both in their highest oxidation state, (+2 for Zinc and +4 for Tin) the material is incapable of further reaction with oxygen and can therefore be considered to have no oxidising properties.

4.17 Stability in organic solvents and identity of relevant degradation products

In accordance with Section 7.15, Column 2 of REACH Annex IX, it is considered appropriate to omit the stability in organic solvents study as the substance is inorganic.

 

4.21 Dissociation constant

In accordance with Section 2 of Annex XI of REACH it is considered appropriate to omit the dissociation constant study as the substance's extremely low water solubility means testing is considered technically not feasible for this substance.

 

4.22 Viscosity

In accordance with Section 2 of Annex XI of REACH it is considered appropriate to omit the viscosity study as the substance is a high melting point solid and this test is technically not feasible for this substance.

 

4.23 Additional physico-chemical information: Transformation/Dissolution

The determination of transformation/dissolution was carried out according to Annex 10 of the United Nations Globally Harmonised System of Classification and Labelling of Chemicals (GHS), First revised edition, 2005(ST/SG/AC.10/30/Rev. 1).

The principles of the test are based on a simple experimental procedure of agitation of various quantities of the test substance in a pH buffered aqueous medium. Sampling (and analysis) of the solutions is performed at specific time intervals to determine the concentrations of dissolved metal ions in the water. The test comprises a screening transformation/dissolution test, a full transformation/dissolution test and method validation.

 

However, after the full transformation/dissolution test there were insufficient data for transformation/dissolution kinetics to be calculated.